docs: def device_added(self, device):
          """Show discovery notification for specified device object."""
          if not self._mounter.is_handleable(device):
              return
          if self._has_actions('device_added'):
              # wait for partitions etc to be reported to udiskie, otherwise we
              # can't discover the actions
              GLib.timeout_add(500, self._device_added, device)
          else:
              self._device_added(device)